1974 Shadow DN-4 CanAm "Championship Winning Car"

In 1974, the last year of the Can-Am, the Shadow DN-4 dominated the series winning 4 of the 5 races. Drivers were Jackie Oliver and George Follmer. The Shadow DN-4 was a new design for that year designed by Tony Southgate, and proved to be an extremely quick car that was relatively easy to drive. The Porsche 917-30's that had won the 1973 Can-Am championship were not running in 1974, but it is interesting to note that the Shadow DN-4's were running with comparable lap times. General Information Below is an extract from Pete Lyons' definitive book on the Can-Am series entitled "Can-Am". Cars of the Can-Am 1974, Shadow DN4 At the beginning of the Can-Am, a designer’s mind was free to roam almost anywhere. By the end, his pencil was nearly as tamed as in any conventional formula. Both mind and pencil still could be kept sharp to get the best performance within the rules, of course, and the significant new design factor in 1974 was limited fuel capacity. Up through 1973, Can-Am cars could carry as much gasoline as the engine might require to cover race distances up to 210 miles. The superpowerful Porsche 917/30 was built as a veritable fuel tanker. For 1974, however, SCCA took ‘energy measures’ which, in final analysis, gave the cars a maximum fuel allowance of 37 gal. Thus was established a much smaller tank around which the designers might shrink their cars, and Shadow took advantage of it. Compared with the bulky, unsuccessful DN2 of 1973, the DN4 was a more compact, lighter vehicle built around tanks displacing a total of 45gal. Wheelbase was increased by 2in to 105, but track dimensions and overall width were narrowed. Otherwise the DN4 was basically conventional in layout and similar to the previous Group 7 model both inside and out. The easiest way to distinguish the two visually was the shape of the front inlets, which changed from rectangular to circular on the new car. Radiators were now carried farther aft in the flanks, and air came to them through troughs either side of the swelling cockpit. Also, the front fender profiles were smoother and wrapped more tightly around the 13in wheels that replaced the 15s of 1973. Fifteens remained at the rear, but plans to mount tires with an outside diameter of 26.5in fell through when Goodyear could only supply the older 28s. That was enough of a discrepancy to require a late geometry redesign. Under its glossy black skin, the 1974 car adopted some suspension parts from Shadow’s new DN3 F1 design. The rear suspension had a total of four trailing radius rods with parallel lower transverse links, instead of single top rods and a lower wishbone. Brakes were still outboard at the front, inboard in back, and the transaxle was still a four-speed Hewland. Perhaps unexpectedly, given the fuel limitations, the Chevrolet-based engine remained at 495ci. However, Lee Muir found that assembling the fuel metering system with greater precision not only yielded the necessary mileage increase, but an additional 35hp as well. Though PR materials quoted 735hp, the same number given the year before, the real 1974 output is thought to have been closer to 800. ‘There’s no substitute for horsepower,’ George Follmer recently told writer Preston Lerner for Sports Car International, ‘but chassis-wise, the DN4 pointed in well and was very predictable. And because frontal area was so small, it was fast in a straight line. It was an extremely good race car.’ It was, in fact, the last great Can-Am car.

History

This car, DN4-1P, was the first of five cars and is regarded as the prototype car. The car was driven extensively by George Follmer and was heavily crashed at Mosport in the Spring of 1974. The car was kept in the possession of Don Nichols' Shadow Cars until he totally rebuilt it; after which it was sold to me directly.